Set NSMutableArray to the new NSMutableArray

Question

@implementation RightViewController{
    NSMutableArray * tableArray;
}

@synthesize tableView;

- (void)viewDidLoad {
    [super viewDidLoad];
    tableArray = [[NSMutableArray alloc] init];
}


- (void)refreshTable: (NSMutableArray*)resultsArray{
    [tableArray setArray:resultsArray];    
    NSLog(@"resultsArray : %d : %d", [tableArray count] , [resultsArray count]);

    [self.tableView reloadData];
}

It shows me : resultsArray : 0 : 78

Why can't I set information to this array? I do call refreshTable from another controller like this:

[[[RightViewController alloc] init] refreshTable:resultsArray];

Updated:

tableArray = [NSMutableArray arrayWithArray:resultsArray];

worked for me.

After that i do

- (IBAction)reloadTableButton:(id)sender {
    [self refreshTable:tableArray];
}

and it's shows me : resultsArray : 0 : 0

Why is tableArray array empty?

It doesn't work because your ivar is always an empty array, and I guess that your tableView data source is baked by said array. — Alessandro Vendruscolo
– Alessandro Vendruscolo, Commented Nov 21, 2012 at 8:34

Yuliani Noriega · Accepted Answer · 2012-11-21 08:47:33Z

1

Try setting your tableArray variable like so :

tableArray = [NSMutableArray arrayWithArray:resultsArray];

You might not be retaining your mutable array I would suggest making a @property for your tableArray. Place this before your @synthesize

@property (retain, nonatomic) NSMutableArray *tableArray;

edited Nov 21, 2012 at 8:47

answered Nov 21, 2012 at 8:22

Yuliani Noriega

1,08312 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Dark Matter Over a year ago

Worked for me. Can you see that is wrong with updated info in a question?

Hermann Klecker Over a year ago

That should work better. But the reason is not that setArray was wrong in any way. The reason might be that viewDidLoad may not have been called before refreshTable is executed. And Victor did not initialize his array in init but in view did load. Therefore setArray may have been sent to a nil object and count may have been sent to a nil object. It should therefore return 0 nor nil. Your suggestion is fine and moving tableArray = [[NSMutableArray alloc] init]; to the init method should work as well.

Hermann Klecker · Accepted Answer · 2012-11-21 17:18:43Z

Option 1:

- (void)viewDidLoad {
    [super viewDidLoad];
    //don't do anything with the array here! 
    //refreshTable may well be called before the view is loaded
}


- (void)refreshTable: (NSMutableArray*)resultsArray{

    if (!self.tableArray) // if it does not exist, then create it on the fly. 
        self.tableArray = [[NSMutableArray alloc] init];
    [tableArray setArray:resultsArray];    
    [self.tableView reloadData];
}

Option 2:

- (MyClass*) init {
  self = [super init];
  if (self) {
     self.tableArray = [[NSMutableArray alloc] init];
  }
}

- (void)viewDidLoad {
    [super viewDidLoad];
    //don't do anything with the array here! 
}


- (void)refreshTable: (NSMutableArray*)resultsArray{
    [tableArray setArray:resultsArray]; // you can be sure that init was invoked earlier.    
    [self.tableView reloadData];
}

Option 3:

- (void)viewDidLoad {
    [super viewDidLoad];
    //don't do anything with the array here! 
}


- (void)refreshTable: (NSMutableArray*)resultsArray{
    self.tableArray = [NSMutalbeArray arrayWithArray:resultsArray];   //This creates a new array as a copy of resultsArray and assigns it to tableArray. No need to initialize anything. 
    [self.tableView reloadData];
}

Andrey Chernukha · Accepted Answer · 2012-11-21 08:30:28Z

0

i believe it should work

RightViewController *controller = [[RightViewController alloc] init];
[controller refreshTable:resultsArray];

answered Nov 21, 2012 at 8:30

Andrey Chernukha

21.9k18 gold badges102 silver badges169 bronze badges

2 Comments

Ben Over a year ago

Your answer would be considerably better if you could explain why.

Hermann Klecker Over a year ago

I would not sign in blood that viewDidLoad has been called before refreshTable is invoked.

Shamsudheen TK · Accepted Answer · 2012-11-21 09:56:19Z

0

@implementation RightViewController{
    NSMutableArray * tableArray;
}
@property (strong, nonatomic) NSMutableArray *tableArray; //use the keyword "retain" instead of "strong" in below iOS 5

@synthesize tableView;
@synthesize tableArray;

- (void)viewDidLoad {

    [super viewDidLoad];
    self.tableArray = [[NSMutableArray alloc] init];
}


- (void)refreshTable: (NSMutableArray*)resultsArray{

     self.tableArray = resultsArray;

    NSLog(@"resultsArray : %d : %d", [tableArray count] , [resultsArray count]);

    [self.tableView reloadData];
}

answered Nov 21, 2012 at 9:56

Shamsudheen TK

31.4k9 gold badges72 silver badges103 bronze badges

Collectives™ on Stack Overflow

Set NSMutableArray to the new NSMutableArray

4 Answers 4

2 Comments

Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related